Project Description

Rosette Nebula/NGC 2237

The Rosette Nebula/NGC 2237, Caldwell 49 in Monoceros is a showpiece astrophotography object for telescopes of any size, resembling a large open flower with an open cluster of stars (NGC 2244, Caldwell 50) in the darker center. It lies about 5,200 light years away and is 130 light years across. The stellar winds from these young, hot stars are clearing the center portion of the nebula, but their ultraviolet radiation is so strong that it still causes the rest of the nebula to glow. Initially, 36 stars were identified to make up the cluster, but Chandra space telescope X-Ray data increase that number to about 160 stars and showed that this is a place of new star formation from all the dust and gas. Note the huge, dark spires of dust projecting toward the center of the Rosette.

A wide-field system is needed to show the full extent of the Rosette. This is a close-up view showcasing the central structures. Narrowband filters were used to bring out the amazing central structures with a total of 25 hours of exposures. The Hubble Color Palette was used where oxygen (OIII), hydrogen (H-a), and sulfur (SII) were mapped to blue, green and red, respectively, in the same way the famous “Pillars of Creation” image was processed. As such, we describe this image as “false color”. An additional 2.5 hours of RGB data were used to provide natural star color, especially to show the intensely beautiful open cluster.


Constellation: Monoceros
Ra: 6hr 32m 18s
Dec: +4d 52m 0s
Distance: 5,200 light years
Image Size: 35′ x 35′
North: Upper right
Image Credit: Don Goldman, PhD

Exposure: Total 27.5 hrs: H-a 10 hrs, OIII 7 hrs, SII 8 hrs, RGB 2.5 hrs
Telescope: PlaneWave CDK20 20
Mount: PlaneWave Ascension A200h
Oag: Astrodon MonsterMOAG
Acquisition: CCDAutoPilot5
Calibration: CCDStack2
Observatory Site: Siding Spring,, NSW, Australia
Camera: Apogee U16M D09
Filters: Astrodon Gen2 LRGB, 3nm H-a, OIII, SII
Guider: SBIG ST-i
Camera Operation: MaximDL5.24
Processing: Photoshop CC
Image Date: 01/09/2014 – 01/27/2014

View more of Don Goldman’s images at